check other parts in std where multi-thread sync is needed

[xxshady]

in the process of fixing #7 and #9 i've discovered that rust std uses dbghelp.dll on windows which itself is single-thread library but std synchronizes access to it for multiple threads by using mutex. in case of relib this mutex wont help because every module (dynamic library) has its own std which has its own mutex for dbghelp.dll

[xxshady]

the cause of #4 is probably related to multiple rust std's of modules in host process